Industrial facilities operating in the marine environment, such as water pipes, power plant water intake systems, sewer pipes, boat hulls, propellers, heat exchangers, grids, fish nets, cages, etc, are prone to marine biofouling. Marine microorganisms such as bacteria, algae, fungi, and protozoa attach to the exposed marine surface and establish colonies, which result in the formation of a slime layer (referring as biofilm). The development of biofilm can also refer to microfouling that not only serves as a source of chemical cues for settlement of invertebrate larvae and algal spores—leading to establishment of macrofouler communities (macrofouling), but also secretes harmful chemicals to building materials of ship hull (corrosion). Macrofoulers such as mussels, tubeworms and barnacles with a calcareous shell or tubes are particularly troublesome as they frequently clog pipes or become attached to submerged surfaces and thus interfere with normal maritime operations.
Biofouling (both microfouling and macrofouling) of underwater structures results in significant economic losses to industry. Decreased fuel efficiency, increased cleaning and maintenance expenses, as well as outage expenses all contribute to increased economic expenditures. Marine bacteria and marine invertebrates such as Hydroides elegans and Balanus amphitrite are the main factors causing biofouling and biocorrosion. Fouling and biocorrosion are interrelated phenomena and cause significant problems and expense to the shipping industry and mariculture. Biofouling can increase the frictional force on a ship's hull by at least 10%, decrease the power of the propellers by 20%, and require over 50% more fuel to maintain a ship at a desired speed. Furthermore, biofouling can accelerate ship hull corrosion by 200% and shorten the life-time of ship hulls by 50%. Economic and environmental losses due to biofouling have amounted up to several billion US dollars annually. Production of toxic antifouling coatings as well as disposal of the spent coatings has caused another several billions of US dollars per year. Over the last 30 years, TBT-based antifouling coating has been the most effective antifouling paints, however, due to its highly toxic nature and considerable and persistent stress on the marine environment, production of TBT-based marine coating has been banned in 1 Jan. 2003 (IMO, 2003). There is an urgent need to find new environment friendly antifouling compounds.
Microorganisms are a sustainable biological source, which may provide new clues for solutions to the problems we are facing today. The use of microorganisms has advantages in reproducible production on a large scale as compared with the use of higher animals or plants. In addition, the microbial fermentations are economically favorable due to low manpower requirements for operation of the fermentation process. Of course, once suitable chemicals originated in marine microorganisms are identified for their antibiotic and antifouling effects, those compounds may be more economically produced by chemical synthesis on an industrial scale.